To investigate the relationship of cardiovascular risk factors with body composition, including fat, muscle and bone mineral density, we entered into an agreement with the NHLBI (Y02-AG-4-0251) and researchers at University of Pittsburgh and the University of California at Davis to obtain body composition measurements with dual energy x-ray absorptiometry (DEXA) during a regularly scheduled visit of the Cardiovascular Health Study cohort. Data collection was completed in October of 1995 and we received data for analysis in July 1996. Bone mineral density has been reported as a risk factor for stroke mortality and stroke incidence in the Study of Osteoporotic Fracture. It has been hypothesized that this is not a direct relationship but may be mediated by subclinical disease which both increases risk of stroke and is associated with lower bone mineral density. Nesting a study of bone mineral density in the Cardiovascular Health Study would allow for examination of the cross-sectional association of subclinical cardiovascular and cerebrovascular disease and then to examine, with repeat MRI, the association of bone mineral density with incident subclinical and clinical stroke. In addition, this data base will allow assessment of the relationship of body fat and muscle with cardiovascular risk factors, particularly insulin and glucose metabolism, weight change, and risk of disability, all important factors in assessment of frailty and prevention of disability.